<!DOCTYPE html>
<html>
<head>
  <style>
    /* 隐藏popup窗口，因为我们不需要显示它 */
    body {
      width: 0px;
      height: 0px;
      overflow: hidden;
    }
  </style>
</head>
<body>
<script src="popup.js"></script>
</body>
</html>
